This invention relates to an improved conveyor pallet construction which is especially useful for multiple work station, assembly lines wherein a separate operation is performed at each of the stations, and further wherein the operation performed at each separate station requires that the pallet construction be fixed or stationary for a discrete period of time at that station.
Jacoby et al in U.S. Pat. No. 3,818,837 discloses a vehicle and track system which is especially useful for manufacturing processes that require a series of separate work stations along a conveyor path. The Jacoby patent teaches a mechanism which provides for transfer of pallets between the separate work stations and also includes a means which permits the pallets to accumulate, in line behind a pallet retained at a work station while a manufacturing operation is performed at that station.
Specifically, Jacoby et al teaches a mechanism which utilizes a continuously operating, rotating longitudinal shaft that cooperates with a drive wheel mounted on a movable work pallet. The pallet is supported on guide rails by rollers and moves along the guide rails in response to motive force received from the rotating shaft. The orientation of the drive wheel mounted on the pallet relative to the longitudinal drive shaft dictates the drive force imparted by the drive shaft to the work pallet. A control arm projects from the drive wheel and is responsive to the position of one work pallet with respect to the next adjacent work pallets. Thus, the proximity of one work pallet to the next will control the drive force imparted to the next adjacent pallet. In this manner when pallets approach each other closely, the drive force thereon substantially terminates because the control arm causes the drive wheel to disengage from the motive force of the drive shaft.
While the aforesaid construction described in the Jacoby et al patent is extremely useful, there remain some unresolved problems associated with such a construction. For example, work pallets have heretofore been supported on a pair of parallel tracks with the drive shaft therebetween. The drive shaft may be positioned above or below the pallet. Access to the pallet, however, may be restricted by this arrangement. Thus, a work station operation which requires access to both the top and bottom side of the pallet simultaneously was not readily possible with the prior art construction.
The present invention overcomes such difficulty by providing a cantilever supported work pallet. Thus, an operation may be performed on the work pallet on both the bottom or the top of the work pallet. Uniquely shaped items may be supported by such a work pallet. Access to the item being processed on the work pallet is much easier.